The present invention relates to control valves. More particularly, the present invention pertains to a displacement control valve in a variable displacement compressor employed in a vehicle air conditioner.
A typical automobile has a compressor that varies the temperature of the passenger compartment for making the ride comfortable for passengers. Such compressors include a variable displacement compressor having a swash plate. The swash plate is tiltably supported on a drive shaft of the compressor. The inclination of the swash plate is changed in accordance with the difference between the pressure in a crank chamber and the suction pressure of the compressor. Rotation of the swash plate is converted into linear reciprocation of pistons.
Such a compressor includes a control valve for controlling the displacement of the compressor. The valve adjusts the pressure in the crank chamber and the suction pressure for controlling the refrigeration performance of the compressor.
Japanese Unexamined Patent Publication No. 1-177466 discloses such a control valve. This valve includes a housing and a solenoid coil secured to each other. The valve also has a valve body and a valve hole. The valve body is moved by the solenoid coil thereby changing the opening amount of the valve hole. Specifically, the valve body is moved by changing the magnitude of current supplied to the solenoid coil. The opening of the valve hole is adjusted, moved by changing the magnitude of current supplied to the solenoid coil. The opening of the valve hole is adjusted, accordingly. A supply lead wire is connected to one end of the solenoid coil and a ground lead wire is connected to the other end of the solenoid coil. The lead wires extend from the control valve. A connector is attached to the end of the supply lead wire. The connector couples the supply lead wire to an electrical power source. The end of the ground lead wire is connected to a fastener such as a ground clamp. The ground lead wire is grounded, or electrically connected to the body frame of a vehicle, by the fastener. In other words, an extra device such as a ground clamp is required for ground the ground lead wire. This increases the number of parts and thus raises costs.